1907.] 



On Globulins. 



421 



Amongst the attributes of colloidal solutions is the possession of an 

 abnormally high viscosity. Judged in this respect, the salt globulin solutions 

 are only slightly colloidal as compared with the solutions of alkali or acid 

 globulin. They differ also from acid and alkali globulin in the relatively 

 greater definiteness of the relations between the components. Dilution of a 

 solution of salt globulin, for instance, brings about a sharp separation of solid 

 and liquid. No such clean saturation points are found with the other two 

 systems. The definiteness of the relations makes it possible to compare the 

 system — neutral salt, water, globulin with other similar three-component 

 systems. 



Data sufficient for the purpose can be obtained from the measurement of 

 the solubility of globulins in aqueous salt solutions made by Osborne and 

 Harris,* and by Mellanby.f The curves which these authors give fail to 

 show the true relations, since only two co-ordinates are used, namely for the 

 salt and the globulin ; the third component, water, is neglected. For the 

 following curves, trilinear co-ordinates are used in the manner recommended 

 by Stokes. 



Fig. 1 shows curves plotted to scale from values derived from Osborne and 



* ' American Journal of Physiology,' vol. 14, 1905. 

 t Loc. cit. 



